For most of Christian America, this is not an age of baptism. Among Southern Baptists, the country's largest evangelical Protestant denomination, the ritual has been in steady and steep decline. The same is true in mainline denominations, which are shrinking in general; Presbyterian churches, for example, have seen slow movement away from the rite for kids and adults for at least the past several years. The trend is most pronounced in the Catholic world: Last year, there were roughly half as many adult baptisms and roughly 25 percent fewer infant baptisms than there were a decade ago, according to this year's Official Catholic Directory.
Not so in the Assemblies of God. The Pentecostal denomination, which had roughly 3.1 million members in the United States as of 2013, has seen a steady rise in water baptisms over the past two and a half decades. But it has also seen steady participation in another kind of ritual: "Holy Spirit" baptisms, or an encounter with the divine that causes someone to speak in tongues. On the Assemblies of God website, the ritual is described as "a special work of the Spirit beyond salvation." The site cites several passages in the Bible, including experiences of Paul and Peter on the Pentecost in Acts, when the Holy Spirit is said to have descended upon the apostles. And, the site says, it can happen to anyone: "We believe the baptism in the Holy Spirit with the initial physical evidence of speaking in other tongues is the promise of the Father to every Christian who desires the experience."
Last year, roughly 2.7 percent of members of the Assemblies of God reported experiencing this kind of encounter with the Holy Spirit. Although instances of this kind of baptism has declined a little since 1997, they have been mostly consistent.
Baptisms in U.S. Assemblies of God, 1979-2013
There could be many reasons why baptismal rites are declining in certain Christian denominations while they're thriving in others: It could have to do with individual church leaders, overall attendance, or even the social environment in Pentecostal congregations, which often involves spirited praying and singing. This is interesting from a religious perspective, but it's also sociologically fascinating—as are Holy Spirit baptisms themselves.
In the academic world, the word for speaking in tongues is "glossolalia." According to a 1972 paper by William J. Samarin in the journal Language in Society, the linguistic definition is "unintelligible extemporaneous post-babbling speech ... without having consistent syntagmatic structure and that is not systematically derived from or related to known languages." (In case you don't keep a dictionary by your computer, or your fingers are broken and you can't use Google very well, "syntagmatic structure" means a combination of words that follow the logical rules of any language.)
Even though this kind of speaking is described as "post-babbling," it has a few surprising characteristics. People are more likely to speak in sounds that are common in their language, Samarin writes, but they also tend to stay away from sounds that are too similar to their native dialect. So, for example, "a speaker of one of the easily recognized regional dialects in the United States, like 'Southern', seems to avoid the diphthongs that characterize that speech."
What this means is that people who are part of churches affiliated with the Assemblies of God in other countries (about 66 million people worldwide) probably all sound different when they speak in tongues—it might not sound like Spanish or Hindi or Portuguese, but it won't sound like Tennessee English, either.
What might be the same across countries is the performance of the experience. The purpose of the recitation has a lot of influence on how it comes out, Samarin writes—the speech will sound different if it's ostensibly a message from God or if it's a personal prayer offered in private.
When people are praying 'round the circle', each one taking his turn, their prayers in tongues—as when they pray in natural language—tend to be of the same duration, as if they had all agreed to divide the total amount of time devoted to prayer equally. Public messages never seem to be as long as sermons or testimonies, but they have their own common duration .... Since a message is given with the conviction that it contains important in formation from God, the speech is faster (perhaps because the message is urgent) and the volume greater.